Field of Invention
This invention generally pertains to a method and apparatus for lifting and repositioning at least partially hollow objects such as ingot molds and like objects. Oftentimes, it is necessary or advantageous to move upright objects and then to reposition the object on its side. This invention is especially suited to perform repositioning tasks of this nature.
In the case of ingot molds, cleaning has been accomplished while the mold is in an upright position with use of chain flails which travel in a vertical fashion. Cleaning is performed for the purpose of improving the surface quality of the steel ingots which are cast in the molds. Upon use and exposure of the temperatures of molten steel the interior mold surfaces become subject to heat checking. Heat checking is manifested in a series of small cracks and fissures which then lead to a deterioration of ingot surface quality upon casting of the ingot. The purpose of ingot cleaning, thus, is to minimize these cracks as well as provide a clean surface for the casting process. One of the advantages of this invention is that the ingot molds may be easily placed on a longitudinal position to facilitate cleaning. The molds may then be advantageously cleaned in the manner set forth in co-pending application U.S. Pat. No. 4,407,037, filed on Aug. 25, 1981, and entitled "MOLD CLEANING APPARATUS".
Inasmuch as the mold is placed on its side, air can more easily pass through the open mold, thereby considerably improving cooling time of the mold. Moreover, ease of cleaning of the mold bottom is enhanced and visibility for inspection or other purposes is greatly facilitated.
The repositioning advantage is obtained with use of the method and apparatus of the invention because the invention is especially adapted to lift and reposition ingot molds and like shaped objects. Others in the prior art have designed lifting devices to move such objects. Examples of these devices include U.S. Pat. Nos. 2,925,300; 2,945,609; 3,190,685; 3,333,883; and 3,436,116. Although these patents involve grapples which engage one side and the central opening of the object being lifted, none of the patents are believed to teach the highly advantageous combination of advantages possessed by this invention. Such advantages and improvements to the art will become more apparent to those skilled in the art from the following description of the invention.